Relay



Sept. 17, 1929. O, s, JENNlNGS I 1,728,550

RELAY Filed Aug. 6, L92() v v v WITNEssl-:s: INVENTOR Q Q; MM5 'OM/ef" 3; Jennings.

l BY

A ATTORNEY Patented Sept. 17, 1929 UNITED STATES PATENT OFFICE OLIVER S. JENNINGS, F BROOKLYN, NEW YOR, ASSIGNOR '.lOL 'WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OFv PENNSYLVANIA RELAY Application led August 1920.. Serial No. 401,619.

Myinvention relates to relays and particularly to electromagnetic relays.

One object of my invention is to provide an electromagnetic relay for an electric circuit that shall reproduce temperature conditions corresponding to the conditions in the apparatus connected to the circuit and that shall operate to disconnect the apparatus from the circuit when predetermined temperature conditions obtain in the apparatus.

Another object of my invention is to provide a unitary relay device, of the above-indicated character, that may be inserted into fuse terminals.

A further object of my invention is to provide a relay device, of the above-indicated character, that shall be simple and economical in construction, and reliable in its operation.

In practicing my invention, I provide a unitaryd relay device comprising a magnetizable core member, a non-magnetizable rod member that is adapted'to pass therethrough and that has a magnetizable member mounted thereon to serve as a movable armature member, and a plurality of windings disposed around the core member. The windings are dilerentially disposed with res ect to each other and comprise a winding, or example,

l of copper and a winding of phosphor-bronze wire. The windings are connected in parallel between two ferrules that are adapted to be inserted into fuse terminals and are so arranged that the ampere turns of the two wind- 'ings shall be normally balanced. That is,v

since the windings are connected between the same points of the circuit, the number of turns of eachwinding will be determined according to the relative resistance of `each. metal that constitutes the conductor.

40 Since the windings are differentially disposed with respect to each other, the resulting magnetizing force is too small to operate the relay while the temperatureof the relay remains below a predetermined value. When the temperature of the relay windings attains a predetermined value, however,.by reason of a heavy overload or short-circuit, the values of the resistance of the respective windings so change as to unbalance the magnetizing :forces and energize the core member suiciently to actuate the armature member and the rod member. It has been observed, moreover, that a sudden rush of current, such as is effected by short-circuit conditions, actuates the relay very quickly. Y

A contact member that is mounted at one end of the rod member disengages a stationary contact member that is mounted at the corresponding end of the relay, when the rod member is actuated by movement of the armature member,l and opens an auxiliary circuit that is normally closed through the contact members. The operation of the relay embodying my invention is dependent, therefore, either upon the temperature of the relay windings attaining a predetermined Value corresponding substantially t0 the temperature of the apparatus in circuit therewith, or upon the current in the circuit exceeding a predetermined value at a redetermined temperature in the relay or t e apparatus.

In the accompanying drawing, Fi ure 1 is a diagrammatic view of a system em odying my invention; n v

Figure 2 is a side view, partially in elevation and partially in section, of the relay embodying my invention;

Figure 3 is a diagrammatic view of the` device of Fig. 2, showing the relation of the respective windings and the contact members;

Figure 4 is a front elevational view of the core member embodied in the device' shown in Fig. 2; and

Figure 5 is a plan view of the core member shown in Fig. 4.

A supply circuit 1 receives energy from a source 2 of electromotive force and is ada ted to Supply energy to a distributing circ it A3 through a circuit interrupter 4. The distributing circuit 3 is provided with a plurality of protective relay devices 5 that arev adaptedAto permit the circuit interrupter 4 to open when overload, short-circuit or lowvoltage conditions obtain in the circuit 3. The interrupter 4 is provided with an electromagnet 6 and a restraining spring 7. The electromagnet 6 maintains the interrupter 4 in its closed position when energized and permits the spring 7 to open the interrupter when the electromagnet becomes de-energized.

The relav comprises a magnetizable core member 8, a movable armature member 9 and a rod 10 of non-magnetizable material upon vwhich the armature member 9 is mounted.

'The armature member 9 is of spool shape and co-operates with an enclosing insulating shell 11 to guide the rod member 10. The rod 10 has a contact member 12 disposed at one end thereof, and a spring 13 disposed at the other end thereof with an adjusting member 14 for varying the amount of compression in the s ring 13 to change the operating point of the relay.

The insulating shell 11 encloses the core member 8 and the armature member 9 and has a plurality of ferrules 15 and 16 disposed at the respective ends thereof. The ferrule 15 is threaded at its end to permit the adjusting member 14 to extend therethrough and the ferrule 16 is apertured to permit a bushing member 17 to extend therethrough. The bushing member 17 serves to support acontact member 18 that is disposed adjacent the movable contact member 12 and a terminal 19 that is disposed outside of the relay to permit the connection of an external conductor thereto.

Two windings 2O and 21that may be of copper and of phosphor-bronze,y respectively, are differentially disposed around the shell 11 between the ferrules 15 and 16 and have their respective terminals connected to the ferrule members 15 and 16, respectively. The rod 10 is electrically connected to the ferrule member 15 through the spring member 13 and the adjustable member 14, and serves in cooperation with the contact members 12 and' 18 to complete an auxiliary external circuit.

At a predetermined temperature, normally corresponding to substantially the average room temperature, the values of resistance of the respective windings 20 and 21 arel such that the magnetizing forces produced by the twowindings 20 and 21, when energized, substantially counterbalance each other and maintain a substantially negligiblemagnetizing effect upon the magnetizable core member 8. As the circuit current traverses the relay 5, the windings 20 and 21 become heated in laccordance with the heating of the electrical apparatus that is connected to the circuit and reproduce substantially the same temperature conditions that obtain in the electrical apparatus. Since the two windings 20 and 2l have different resistance temperature coeiiicients and are dierentially disposed, with respect to each other, about the core member 8, the effective magnetizing force that acts upon the. core member 8 will increase as the temperatures ofthe windings increase to change the relative values of the resistance thereof. When the value of the magnetizing force that4 energizes the core member 8 becomes suiiicient to establish an attractive effect on the armature 9 that corresponds to the weight of the armature 9 and the compression force of the spring 13, the armature member 9 will be lifted and the contact members 12 and 18 will be disengaged. Since the effective magnetiz'ing force varies in accordance with the temperature conditions in the relay 5, the spring member 13 may be so adjusted that the relay will operate at such predetermined values of current as will produce predetermined temperature conditions in the relay 5. The core member 4 is slotted, as illustrated in Figs. 4 and 5, to prevent the establishment of eddy currents therein.

The electromagnet 6 serves to maintain the interrupter 4 in its closed position while normal conditions obtain in the circuit 3. Upon the occurrence of overload or short-circuit conditions, however, the traversal of excessive currents through the relay will so heat the same as to cause them to open the auxiliary circuit that energizes the magnet 6 and permit the interrupter to be opened. Similarly, an occurrence of low-voltage conditions will so decrease the energization of the magnet 6 as to permitthe interrupter to open.

Although I have shown a preferred form of device embodying my invention, I do not limit it to the specific structure illustrated, as various modifications may be made therein within the spirit and scope of the invention as set forth in the appended claims.

I claim as my invention:

1. A relay comprising a magnetizable core member having a longitudinal opening throughout its length, a non-magnetizable rod member adapted to move therein, a contact member controlled by the rod member, a magnetizable armature member mounted on the rod member and adapted to actuate the rod member, and two windings differentially Wound with respect to each other for actuating the armature when the temperature of the windings attains a predetermined value.

2. A relay comprising a magnetizable core member having a longitudinal opening throughout its length, a non-magnetizable rod member adapted to move therein, a contact member controlled by the rod member, a magnetizable armature member mounted on the rod member and adapted to actuate the rod member, and two windings having diflferent thermal characteristics and differentially wound with respect to each other for actuating the armature member.

A relay comprising a magnetizable core member, a movable armature member, a contact member controlled by the movement of the armature member and a plurality of coaxial windings diferentially wound with respect to each other for actuating the armature member when the temperature of the windings attains a predetermined value.

4, A unitary relay device adapted for use with fuse receptacles comprising a magnetizable core member, a movable armature member therefor, a Contact member controlled by the armature member, adjusting means for the armature member, a supporting member for the armature member, a plurality of differential windings for actuating the armature member and a plurality of errules on the ends of the supporting member for connecting the windings in an electric circuit.

5. A. unitary relaydevice adapted for use with fuse receptacles comprising a magnetizable core member, a movable armature member therefor, a contact member controlled by the armature member, a supporting and enclosing shell for the core and the armature members, a plurality of windings for actuating the armature member and a plurality of ferrules on the supporting shell, between which the windings are connected, and adjusting means for the armature member eX- tending through the ferrule.

6. A unitary relay device adapted for use with fuse receptacles comprising a magnetizable core member, an armature member therefor, a contact member controlled by the armature member, insulating means for enclosing and supporting the core, the armature and the contact members and having contact members at the respective ends thereof adapted to contactively engage fuse receptacles, and a plurality of diierential windings disposed on the insulating means for actuating the armature member.

7. A thermal relay comprising a tubular member of insulating material, a magnetizable core member disposed inside the tubular member at one end thereof and supported thereby, a bushing of insulating material disposed at the other end of the tubular member and supported thereby, astationary contact member disposed on the inner surface of the bushing, a terminal member extending therethrough to permit the contact member to be connected to an external circuit, a movable contact member for engaging the stationary contact member, a movable magnetizable armature member for actuating the movable contact member, means for adjusting the operating force necessary to actuate the armature member, two windings disposed on the tubular member to eiect the actuation of the armature member and a ferrule at each end of the tubular member to connect the windings in an electric circuit.

In testimony whereof, I have hereunto subscribed my name this 29th day of July, 1920.

OLIVER `S. JENNINGS. 

